Indirect lighting fixture providing a uniform light distribution



Jan. 16, 1968 R. c. DAMERAL 3,364,348

INDIRECT LIGHTING FIXTURE PROVIDING A UNIFORM LIGHT DISTRIBUTION Filed Sept. 5, 1965 I NVENTOR.

RAY C. DAMERALY ATTORNEYS United States Patent INDIRECT LIGHTING FIXTURE PRUVHDING A UNIFURM LIGHT DISTRIBUTION Ray C. Dameral, Pleasant Hill, Calif, assignor to Herst Lighting Corporation, doing business as Peerless Electric Company, San Francisco, Calif, a corporation of California Filed Sept. 3, 1965, Ser. No. 484,987

8 Claims. (Cl. 240-51.11)

ABSTRACT OF THE DISCLOSURE An indirect lighting fixture is described in which the underside of the light housing is illuminated by reflection so that the fixture is free of the usual undesirable shadows or glare caused by the underside. The lighting fixture comprises an open top housing adapted to be mounted beneath a ceiling so as to illuminate the ceiling. The underside of the housing is opaque but a U-shaped projection is provided at each lonigtudinal edge of the underside and extending below it. The projections have regularly spaced apertures through the side thereof facing the opaque underside of the housing so that light from a light source within the housing will be directed toward the exterior surface of the opaque underside to illuminate the same.

The present invention relates generally to indirect lighting systems. More specifically, it relates to an improved lighting fixture adapted to provide uniform illumination.

Of the various primary and secondary luminous sources, indirect lighting, i.e., lighting by reflection, is beneficial for many reasons. Most importantly, indirect lighting tends to provide an even distribution of light to minimize glare and shadows for visual comfort. The illumination of interior rooms by indirect lighting may be accomplished through a variety of light fixture patterns generally formed from a plurality of light housing units. These various patterns have come to be categorized as row, tier, rectangular, U-shaped, spline and valance systems. In these various indirect lighting systems, the light housing units are placed to direct light upon the walls or ceilings wherefrom the light is reflected to be diffused evenly throughout the area which is to be illuminated. Regardless of the fixture pattern employed, uniformity of illumination of the secondary source is most desirable.

Unfortunately, conventional components employed in constructing the lighting systems often create unwanted dark, glaring or shadowy areas. Generally, the existence of these areas is characteristic of the conventional ballastlight housings comprising the lightin system. For example, one class of conventional indirect lighting systems is constructed with light housings having only their upper portions pervious to light emanating from therewithin. Consequently, light rays emitted by the primary luminous source can only emerge from those upper portions. This results in the undersides remaining dark, hence a lack of uniformity of illumination of the secondary source. Although this can be somewhat alleviated by arranging the housings in a tiered structure, the underside of at least one of the light housings, the lower most of the tier, will be dark. Another approach towards providing uniformity of illumination of the secondary source has involved adapting the undersides of the li ht housings with a translucent or transparent member. However, where the ballast is housed in the same housing as the primary source, either below or coextensive therewith, at least those sections of the underside of the housing subjacent the ballast units will be dark. Of course, where the ballast units are mounted above the primary source, a shadow thereof will be cast on the surface acting as the reflector of the rays of light from the primary source. In addition, the translucent or transparent members often times act as surfaces of excessive brightness when compared to the surrounding surfaces of reflection. Since such light transmitting members are in the line of vision and appear as a source of higher brilliance, they will appear to glare. The presence of such glare, shadows, or dark areas is undesirable since their existence precludes creating a uniformly illuminated secondary source.

Considerable advantage is therefore to be gained by the provision of an indirect lighting system which is capable of establishing a uniformly illuminated secondary light source. The indirect lighting fixture of the present invention provides the means of generating such a uniformity of illumination. More particularly, a light housing is adapted with hollowed projections which communicate to the interior of the housing and extend beyond the underside thereof. The surfaces of the projections which face towards the underside define light previous sections, such as apertures. The light pervious sections facilitate the conductance of light from the primary light source, such as fluorescent light tubes, within the housing to the underside of the housing. The light emerging from the light pervious sections impinges the underside of the housing and illuminates the surface thereof. By adapting the light housing with such light pervious sections, it is now possible to illuminate by reflection those surfaces of the underside of light housings which previously were either not illuminated or sources of glare. As a result of it being possible to reflectively illuminate the underside of the light housings, an enhanced uniformity of illumination of the area being illuminated is accomplished.

Accordingly, it is a principal object of the present invention to provide an indirect lighting system capable of affecting uniformity of illumination.

More particularly, it is an object of the present invention to provide an indirect lighting fixture which is free of undesirable shadows, glare, and darkened areas in the vicinity thereof.

Another object of the present invention is to provide an indirect lighting fixture which is adapted to reflectively illuminate its underside.

A further object of the present invention is to provide a single housing for the ballast and fluorescent light tubes of an indirect lighting system which is characterized by both shadow-free and uniform illumination.

Still another object of the present invention is to provide a single ballast-fluorescent light tube housing which features enhanced distribution of light from the primary source.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the preferred form of the invention which is illustrated in the drawing accompanying and forming part of the specification. It is to be understood, however, that variations in the showing made by the said drawing and descritpion may be adapted within the scope of the invention as set forth in the claims.

Referring to said drawing:

FIGURE 1 is a perspective view of one embodiment of the indirect lighting fixture constructed in accordance with the present invention.

FIGURE 2 is a sectional side view of a section of an indirect lighting fixture of the class portrayed in FIGURE 1 adapted to house both the ballast and fluorescent light tubes therein.

FIGURE 3 is a sectional view taken at lines 33 of FIGURE 2.

FIGURE 4 is a sectional view taken at lines 44 of FIGURE 2.

With reference to the drawings and in particular FIG- URE 1, the indirect lighting fixture 11 of the present invention comprises a housing unit 12 supported to deliver light emanating from within to surfaces which are to function as secondary light sources. For example, as illustrated in FIGURE 1, housing 12 is supported by struts 13 and a stem ball aligner and wiring channel 15 subjacent the ceiling 14 of a room to be illuminated. Struts 13 may be, for example, conventional airplane cables. However, in addition to ceilings, indirect lighting fixtures in accordance with the present invention may be mounted adjacent other horizontally or vertically oriented surfaces, such as floors or walls. The illumination of ceiling 14 is accomplished by mounting a primary light source, e.g., fluorescent light tubes, within housing 12 and adapting the side 16 thereof in facing relation to ceiling 14 to be light previous. The primary light source is energized and with assistance from housing 12 directs its generated light onto ceiling 14, generally a diffuse surface, whereat the light is preferably diffused evenly throughout the room to be illuminated.

As noted hereinbefore, conventional indirect light housing often are characterized in that either their undersides are nonilluminated, or illuminated by transparent or translucent transmission means which act as centers of glare. However, with the lighting fixture of the present invention, uniformity of illumination about fixture 11 is obtained by adapting housing 12 with hollowed projections 17 which extend below the underside 18 of housing 12. The side 19 of projections 17 proximate underside 18 is adapted to be light pervious thereby allowing light from the principal light source within housing 12 to pass therethrough and illuminate underside 18. As shown in FIGURE 1, this light perviousness of housing 12 can be accomplished by constructing side 19 of projections 17 to define a series of regularly spaced apertures 21. It should be noted that the light reaching apertures 21 is not direct but instead is conducted from the primary source thereto by reflections at the inner surfaces of housing 12. Hence, glare at apertures 21 and underside 18 is reduced to a minimum.

' Referring now to FIGURES 2-4, a particular embodiment of the class of indirect lighting fixtures set forth hereinbefore will be described in detail. With particular reference to FIGURE 2, it is seen that housing 12 is adapted to support therein both fluorescent light tubes 23 and ballast unit 22 including a ballast inductor and capacitor of an indirect lighting system. The housing 12 is of an inverted symmetrical trapezoidal cross section mounted with its parallel sides defining the upper and undersides 16 and 18 respectively in planar alignment with the surface to be illuminated. The inverted trapezoidal cross section is preferred because the light generated by tubes 23 is most efficiently reflected by the nonparallel sides 24 and 26 to emerge from the light pervious upper side 16. However, other cross sectional housing configurations may equally be employed.

As can be seen by referring to FIGURES 3 and 4, in accordance with the present invention, the nonparallel sides 24 and 26 are extended to project below underside 18. Sides 24 and 26 connect to underside 18 by a weblike member 27. The extended section of the nonparallel sides 24 and 26 and web-like member 27 respectively connected thereto define respectively a generally U- shaped projection 17 which joins sides 24 and 26 and underside 18. To facilitate the illumination of outwardly facing surface 28 of underside 18, web-like member 27 is adapted to be pervious to light. More specifically, members 27 preferably are provided with the regularly spaced apertures 21, yet any other light pervious means may be adapted to or serve as web-like member 27.

The mounting of ballast 22 and tubes 23 within housing 12 preferably is effected to maximize the distribution of light therefrom. In the case of the present invention, the distribution of light is maximized by mounting ballast 22 and tube 23 within housing 12 in end to end spaced relationship. By so mounting the ballast 22 and tube 23 in a single housing 12 of the character described immediately hereinabove, a compact indirect lighting fixture providing maximum distribution of light with uniformity of illumination is furnished. Although the indirect lighting fixture 11 of the present invention is portrayed in the drawings and has been hereinbefore described as a double lamp unit, it will be appreciated that housing 12 easily can be adapted to accommodate therein more than two fluorescent light tubes 23 and associated electrical apparatus. Additionally, a plurality of lighting fixtures 11 may be arranged in any of the many light fixture patterns, for example, as set forth hereinbefore. Where a plurality of indirect lighting fixtures are to be linked together, such may be accomplished by any of the conventional indirect lighting fixture linking means, e.g., brackets securing two housings 12 in abutting end to end relation.

Considering now the manner in which ballast 22 and light tubes 23 are supported and electrically connected to be energized, it will be seen by referring to the FIGURES 24 that they are mounted on an inverted U-shaped channel member 29. The U-shaped member 29 is mounted within housing 12 to underside 18 to extend longitudinally along housing 12, preferably substantially along its entire length. Inductor 20 and capacitor 25 are mounted to channel member 29 proximate wiring channel 15 of housing 12 by, for example, screws 31. Fluorescent light tube 23 is secured in place within housing '12 by suitable tube sockets 32 (one shown) mounted to channel mem ber 29.

With particular reference to FIGURES 3 and 4 it is seen that the channel sides 33 and 34 of channel member 29 form acute angles with its web section 36. By adjusting this angle so that channel sides 33 and 34 extend from web section 36 away from sides 24 and 26 respectively of housing 12, light encountering the channel sides 33 and 34 will be reflected downward towards apertures 21 eventually to emerge therefrom and illuminate the underside 18 of housing 12.

U-shaped channel member 29 serves another purpose in addition to supporting ballast 22 and tube 23. Specifically, U-shaped channel member 29 defines with underside 18 of housing 12 a channel 37 which serves as a wireway for the various electrical leads required by ballast 22 and tube 23 for operation. Grommets 38 are mounted within web section 36 of channel member 29 at appropriate locations to afford the means for connecting the electrical leads housed in channel 37 to ballast 22 and fluorescent light tubes 23. However, with reference to FIGURES 2 and 3, such connections can also be accomplished by suitable connectors, as for example, two conductor connectors 39 mounted in Web section 36 of channel member 29 to couple energizing power to tube 23 via socket 32.

Indirect lighting fixtures of the character of the present invention predominately are utilized to illuminate areas by directing light to be reflected from a ceiling having a diffuse surface. As noted hereinbefore, housing 12 is mounted subjacent ceiling 14 by struts 13 and wiring channel 15 to project the light generated by tubes 23 through its open upper side 16 onto ceiling 14. Both struts 13 and wiring channel 15 are secured to housing 12 in the same manner with struts secured proximate opposite ends 30 of housing 12 and wiring channel 15 secured proximate its center section. For example, as illustrated in FIGURES 2 and 4, wiring channel 15 is secured to housing 12 by terminal element 39 fixed at one of its ends and mounted to plate. 41. Plate 41 in turn is secured between sides 24 and 26 of housing 12. To keep the electrical leads for delivering power to the indirect lighting system hidden from view, the leads .(not shown) are enclosed within wiring channel 15.

As has been emphasized in the detailed description supra and as shown in the drawings, one important aspect of the present invention is that of uniformly illuminating the underside of an indirect light housing. This was expressly set forth in terms of two light pervious projections extending below the underside of the housing to direct light thereupon. However, the number of such light pervious projections absolutely necessary is one. Furthermore, the number of such projections that can be used is a matter of choice.

What is claimed is:

1. A fixture for an indirect lighting system comprising a housing having a side which is light pervious and adapted to support a primary light source in the interior defined thereby, the side of said housing opposite to said light pervious side being opaque and said housing disposed to have said light pervious side adjacent and in facing relation to a surface which is to serve as a secondary light source; and at least one hollowed projection mounted to said housing and extending below said opaque side of said housing, the surface of said projection facing towards said opaque side being pervious to light and the hollow defined by said projection being in light communication with the interior of said housing whereby light emanating from said primary light source is directed toward the exterior of said opaque side to illuminate the same.

2. The fixture as recited in claim 1 further defined by said housing having a generally rectangular cross section defining upper and under sides and side walls, said upper side of said housing being open to define said light pervious side and the underside being opaque to define said opposite side.

3. A fixture for an indirect lighting system comprising an open top housing adapted to be mounted subjacent a ceiling with its open top in facing relation thereto, said housing including first and second side walls, an opaque underside defining first and second terminal edges, and first and second hollow generally U-shaped projections joining said first and second side walls respectively to said first and second terminal edges of said underside and extending below said opaque underside, the side of each of said U-shaped projections facing towards said underside being pervious to light and said projection being in light communication with the interior of said housing and an end plate mounted to each of the ends of said housing defined by said side walls and underside; and socket means mounted within said housing to support and provide electrical connection to at least one fluorescent light tube.

4. A fixture for an indirect lighting system comprising an open top housing defining an interior adapted to be mounted with its open top subjacent a ceiling, the side of said housing opposite to said open top being opaque; at least one hollowed projection mounted longitudinally of said housing at said opaque side and extending below said side, the surface of said projection facing towards said opaque side being pervious to light whereby light emanating from within said housing is directed by said projection toward the exterior surface of said opaque side to illuminate the same; mounting means for securing a ballast unit within the interior defined by said housing; and mounting means for securing a fluorescent light tube within said interior in end to end spaced relationship with said ballast.

5. The fixture as recited in claim 4 further defined by said mounting means for securing ballast and fluorescent light tube being a generally U-shaped channel member having two sides and interconnecting web which define a channel for electrical leads for energizing said ballast and tube mounted to said web on the side thereof facing away from said channel, said U-shaped channel being mounted within said channel inverted at said opaque side of said housing opposite said open top, said web being provided with grommets extending therethrough for electrical lead passage.

6. A fixture for an indirect lighting system comprising an open top housing adapted to be mounted subjacent a ceiling with its open top in facing relation thereto, said housing having a generally inverted symmetrical trapezoidal cross section defined by parallel open top and underside and nonparallel first and second side walls, said side walls extending below said underside; first and second web members each defining regularly spaced apertures, said first and second web members respectively mounted to join first and second side walls to said underside with said apertures facing the underside; a generally U-shaped channel member having two sides and interconnecting web which define a channel for electrical leads, said channel member mounted inverted within said housing at the underside thereof spaced apart said side walls; a ballast unit secured to said interconnecting web on the side thereof facing away from said channel; socket means and fluorescent light tube secured to said interconnecting web on the same side as and spaced apart said ballast; and grommets mounted within and extending through said interconnecting web proximate ballast and socket means to provide electrical lead passages through said channel member to said ballast and fluorescent light tube.

7. The fixture as recited in claim 6 further defined by said sides of said interconnecting web being inclined to respectively define an acute angle with said first and second nonparallel sides of said housing with its apex oriented upward.

8. The fixture as recited in claim 6 further defined as comprising at least one strut mounted at one end to said housing and whose other end is adapted to secure said fixture to the ceiling.

References Cited UNITED STATES PATENTS 2,703,360 3/1955 Lipscomb 24051.11 2,932,728 4/1960 Thomas 2409 3,117,729 1/1964 Silvers et al. 24051.11 3,246,137 4/1966 Zagel 24051.11

JOHN M. HORAN, Primary Examiner.

NORTON ANSHER, Examiner.

M. SHEER, Assistant Examiner. 

